Lens-surfacing machine



2 Sheets-Sheet l his 61mm,

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c. w. HOWLAND LENS SURFACING MACHINE Filed July 18 1919 Feb. 17, 1925.

- C. W. HOWLAND LENS SURFAQING MACHINE Filed July 18, 1919 2Sheets-Sheet 2 c jvwm doz Chauncey 14 How/and W Q4 MM Patented Feb. 17,1925.

LEZ'LM UNITED STATES PATENT OFFICE.

CHAUNCEY W. HOWLAND, OF GENEVA, NEW YORK, ASSIGNOR TO H. J. STEAD, 0FGENEVA, NEW YORK.

LENS-SURFACING MACHINE.

Application filed July 18, 1919.

T0 aZZ whom it may concern:

Be it known that I, GHAUNCEY W. How- LAND, a citizen of the UnitedStates, residing at Geneva, in the county of Ontario and State of NewYork, have invented certain new and useful Improvements in Lens-Surfacing Machines, of which I declare the following to be a full,clear, and exact description.

This invention relates to machines for grinding and polishing thesurfaces of lenses commonly termed surfacing.

The general type of lens surfacing machine now in common use providesfor the rotation of the grinding tool or lap on the end of a verticalspindle and for the oscillation of the lens across the face of the lapby a hand lever which is pivoted at one end. lVhile adjustments areprovided in those machines whereby the pin connecting the lever and lensblock may be raised and lowered, no provision is made for causing thebody of the pin to describe the are of a circle concentric with the arcof the lap, but on the contrary the pin moves across the face of the lapin fixed angular relation. This has caused uneven pressure on the lensand interferes with the perfect operation of the machine. I aim toovercome this disadvantage by providing means whereby the pin whichpresses the lens against the tool shall describe an arc having the samecenter as the tool so that pressure applied to the lens shall at alltimes be radial to the surface of the tool and be the same in amount,whether the lens is near the center of the tool or near an edge of thesame.

An object of my invention is to provide a lens surfacing machine, whichis simple and durable in construction and efficient in operation on bothstrong and weak lenses.

Another object is to provide such a 1nachine which can be quickly andeasily adjusted to grind or polish convex and concave lenses of eitherstrong or slight curvature, as well as flat lenses.

A further object is to provide such a machine in which the pressurebetween the lens and'the tool against which it is beng ground orpolished may be kept constant regardless of the relative position of thelens.

and tool.

A further object is to provide means for applying pressure between thelens and the tool which shall be directed in a line radial Serial No.311,825.

to the face of the tool and the amount of which may be readily adjustedand held at any desired value.

Further objects of this invention will be apparent from the detaileddescription to follow. I accomplish the objects of my invention in oneinstance by the devices and means described in the followingspecification, but it is evident that the same may be varied widelywithout departing from the scope of the invention as pointed out in theappended claims. A structure constituting an embodiment of my inventionis illustrated in the accompanying drawing, forming a part hereof, inwhich:

Figure 1 is a longitudinal, vertical, sec tional View of the machinewith the parts in position for surfacing a concave lens.

Fig. 2 is an elevation of the machine showing the oscillatable lensguiding frame swung to the left.

Fig. 3 is a fragmentary top plan view of the machine.

Fig. 4: is a sectional view taken on a line t4@ of Fig. 2.

Fig. 5 is a fragmentary elevation corresponding to Fig. 1 showing theindex marks on the two supporting brackets for the frame.

Figs. 6 and 7 are respectively a front elevation and a sectional View ofa modification.

Fig. 8 is a sectional view of the same, taken on the line 8-+'8' of Fig.6.

Referring to the drawing, a base 5 secured to any suitable support, suchas a bench 6 by means of bolts 7, has an upstanding circular post 8 uponwhich is pivoted a bracket 9. This post 8 is provided with an annulargroove 10 into which engages the end of a set screw 11 whereby thebracket 9 is retained on the base member 5, and whereby it may berigidly secured in any desired position by tighten'ng the screw 11. Thebracket 9 has adjustably secured to it a second bracket 1% which brackethas at one end a cylindrical post 15 which like the post 8 has anannular groove 16 formed in its periphery into which engages a set screw17, carried by the frame 18. The frame has an opening to receive post 15and form a bearing thereon. By means of this connec ton the frame 18 mayoscillate about the post 15 being retained thereon by the set screw 17,and by tightening this screw the frame in'ay be heldfirinly inanyd-esired-.po sition. Thebracket 1 1 carries "a bolt'19, having a nutwhose head engages ina T shaped slot'21 fo'rined-in the bracket 9.

bracket 9 has a somewhat spiral form so as to provide sufficientclearance for the bracket 14. By means of this connection the bracket 14may be adjuSttlveftlally on the bracket 9, and may be secured thereto,eitherdependingfrom theb'olt as shown in full lin'esi'n Fig. 1, orinupriglit'position as indicated by dotted lines in'which position thepost 15 engages'in a second similaropening 22. A screw 23 similar toscrew 17 'isfp'rovided to engagethe groove 16 whenthe bracket I l-is inanuprightposition, andby this sciew-23'the fra-me18 maybe retaindonthepost '15, or secured to'theb'racket'14in any desired position.

The roi-wau'poruon of the frame 18 is shaped to receive in slidingengagement" two square rods 25 a1id"26, a plate 27 secured to the'frontface cram frame serving to retain them inproper position. Tlie'rod 25has threaded into it"a pin 28havi-ng a point engaging a recess into alens mounting block 29 and serves to guide the lens over the face of thelap. Into the opposite end of the rod 25 is threaded a rod 31 whichextends up through and has sliding engagement with the rod 26. AL nut'32threaded on the upper end of the rod 31 engages the rod 26' to limit thedownward movement of the rod 25. A gear wheel 34 or segment thereof,having a set's'crew'35, is' rigidly inounted on when 36 j'ou'rnaled inthefraine 18*and is adapted to engage te'eth '37 cut inthe adjacent sideof the rod 26 to thereby vary the tension of a smancom r'ession sprmgssinterposed betweenthetwo rods, 25' and '26. The gear wheel 3+1 isoperated by means ofalever 40 secured to the shaft 'by a'set'" screw 11and this lever is adapted to be automatically held in adjusted positionby means of theclutch device, now to'be described. This clutchdevicecon'i' 'jrises agrooved wheel 43 through which the shaftektendsloosely, and which is held'against' movement by a screw 4-4threaded into' the frame 18. The lever has a lateral extension46 havinga face opposite the periphery: of the groo-ved vheel $53 which face andadjacent portion ofthe periphery of the wheel form a wedge shapedcavity. A ball 17, having a wedging engagement inthis cavity, preventsthe lever from moving ina di'rection' toi'elieve the pressure on thespring 38. A' small, flat spring 48 attached to' the upperfportioir ofthe lever-4O serves to retain' the ball in its place. Topermit raisingthe lever 40 to relieve pressure uponthe spring 38, a second lever 50 isprovided. This lever 50 is pivotally attached to lever 40 by a screw 51and has an extension 52 which is adapted to onga-ge' theundersideoffthe'ball to lift it out of'wedging position. To"avoid the possi-"bility'of'breaking the spring 48 by too great "pressure exerted 1 onthe lever 60," the extra- It will be noted from Figs. 1 and fz'that thesionatdof lever 40 is shaped to provide a stop for lever 50.

Ahandle-to is provided extending forwardly and laterally from the frontportion of the"'frame 18*by means of which the frame may be oscillated.p

In 'order that'the frame and pin shall swing in an'arc concentric withthe center of curvature of the tool, the bracket? is provided-with anindex mark'5'6 and the bracket 14 is-provided'with several index marks.57, Fig. 5 showing three such marks, marked respectively 6, 8 alid 11).These marks refer to the strength of the lens being surfaced, forexample, 6, 8 and 10 diopters. The opposite side of'thebracl tet 14 is:also provided with similar index marks which are adapted to be broughtinto register with the index "market when a convexlensis being surfaced.

The lens holding block 29 is shown carrying a lens being surfaced by thetoolor lap 61, having a convex surface. This tool,

61 is mounted in the usual manner upona spindle 62 extending upthroughthe bench 6 and is shown carrying a protective flanged collar63.The means for mounting and; rotatingthe spindle 62 forms no, pai't ofthis invention, being common construction, and istherefore not shown.

fIn operation supposing it is desired to grind or polish a concave-lens;themachine is set up in the manner illustrated by-Fig 1., the bracket14: engaging the frame 18- in the lower bearing. The screw'll istightened with theportion 21 of bracket Sfacing the too-l and thebracket 14 adjusted with-the index mark on bracket?) opposite theappropriate index mark-onbracket let correspond' ing to -the' lens to beground. The pin 28 is inserted in the opening in block 29' and the leverdepressed to suitably tension thespring 38; This lever having been onceadjusted will cause the lens to'bear upon the lap with an unvaryingpressure throughout the grinding and, polishing operation andre gardlessof the position or the lens on the lap. The tool 61 is rotated by anysuitable means and the frame 18 is oscillated= back andlforth about thepost 15 as a centenfthe lens being" thereby carried back and forth overthe surface of the tool. Since the centerfof oscillation has been set tocoincide with the center of curvature of the tool, the pressure of the.pin 28 willat all tin;1es be radial to that-surface and the tension willbe constant.

If desired the frame maybe secured in a til -ted position, such forexample, as shown in Fig. 2; by tightening the screw 17 it beingpossible to clamp the bracket in any position desired "so that the lensmay be held in whatever position relative to the tool, it may be foundthat the best results are produced. Practice has shown that it is verydesirableto vary the position of the lens on the tool in order that thetool may be worn down evenly and the original curvature retained. Inpolishing it is sometimes found that the lens may polish at the centeror at the edge, in which case it would be desirable to hold the lens insuch position as to cause it to polish evenly over the entire surface.In such event the position maybe selected and the bracket. clamped sothat it will polish in the desired position, clamping of the bracketmoreover will allow the machine to operate while the operator gives hisattention to other machines.

hen it is desired to surface a convex lens, the bracket 14 is secured tothe bracket 9 in its upright position, such being indicated by dottedlines in Fig. 1, and these two brackets adjusted relative to each otherwith their alining index marks corresponding, as in the case ofa concavelens, with the degree of curvature of the tool or lap. As so arrangedthe frame 18 may be oscillated about the bearing 22 as a center.

hen it is desired to surface a flat lens or one whose curvature is lessthan 6 diopters, the frame 18 and thetwo brackets are all securedrigidly together by tightening the appropriate screws and upon looseningthe set screw 11, the entire organization is oscillated in ahorizontalplane about the,

post 8 as a center. As in the case of surfacing convex and concavelenses the lens may be oscillated back and forth over the lap or the setscrew 11 may be tightened to hold the lens in any desired position.

In the modification illustrated by Figs. 6, 7, and 8 there is shown abracket corre sponding to the bracket 1 k and pivotally supported on thebase member This bracket is retained upon and may be fixedly secured tothe post 8 of the base member by means of the screw 11 as in thepreviously described form. The bracket 65 is provided with a groove 66on its front face in which slides a second bracket 67 carrying at itslower extremity a pivot post 68 corresponding to the pivot post 15. Thebracket 67 is provided on its rear face with a longitudinal groove inwhich is mounted and secured a rack 69 and this rack meshes with asmallinion 7 O mounted upon a shaft 71 having iearings in the bracket 65.Upon one end of the shaft 71 is mounted a hand wheel 73 by means ofwhich the pinion may be rotated and the bracket 67 raised and lowered.In order to fix the bracket 67 in any desired position the bracket 65 isprovided with two set screws 7 ti: and 75 which when tightened engagethe side of the bracket 69 to prevent movement thereof, the lower setscrew 7 5 being adapted for use when the bracket 69 is in its loweredposition as shown in full lines by Figs. 6 and 8, and the set screw '74being adapted for use when the bracket is raised to the positionindicated by dotted lines in Fig. 8. When the bracket 67 is in itslowered position the post 68 is adapted to enter the lower bearing ofthe frame 18 for use in surfacing concave lenses. To surface a convexlens the hand wheel is rotated to raise the bracket 67 sufiicient tobring the post 68 into alinement with the upper hearing 22 of the frame18. To provide for the proper setting of the bracket 67 it is providedwith an index mark 7 8 which, when the bracket 67 is in position forsurfacing concave lenses, may be brought to register with appropriateindex mark 79 on the face of the bracket 65. lVith the parts in positionfor surfacing convex lenses the index mark 78 may be brought to registerwith the appropriate index mark 80 also on the face of the bracket 65.

\Vhile I have described my invention in more or less detail, and asbeing embodied in certain precise forms I do not desire or intend to belimited thereto, as on the contrary my invention contemplates broadlyall proper changes, as well as the omission of immaterial elements andthe substitution of equivalents therefor, as circumstances may suggestor necessity render expedient.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a lens grinding and polishing machine, the combination of arotatably mounted tool, a lens guiding frame, a bracket for supportingsaid frame, said frame being constructed to pivotally engage saidbracket at either one of two points located respectively above and belowsaid tool to swing in a plane parallel with the axis of said tool, abase member, a second bracket pivoted to said base member to swing in aplane a right angles to the axis of said tool and adjustably secured tosaid first mentioned bracket to vary the effective radius of movement ofthe lens guided by said frame, means for rigidly securing said frame tosaid first bracket when the frame is to be swung in the last mentionedplane and means for rigidly securing said second bracket to said basemember when said frame is to be swung in the first mentioned plane.

2. In a lens surfacing machine, the combination of a frame, a memberhaving a sliding engagement with said frame for pressing a lens againsta surfacing tool, a lever pivoted to said frame for sliding said member,a member carried by said frame having asurface concentric with thepivotal point of said lever, said lever having a surface adjacent saidconcentric surface and forming a wedgeshapedchamber therewith,

a ball in said chamber and'a devicecarried by said lever for releasingsaid ball from \vedging engagement. v

3. In a lens surfacing machine having a tool against which a lens isadapted to be surfaced} the combination of a frame a member slida-ble insaid frame-adapted to presssaid lens against-said tool, arackconstructed to slide in said frame, a compres sion spring between saidmember and said rackya gearwheel PlVOtGCl in said frame, a

hand *lever operatively: connected to said gear wheel, a second membersecured to said frame having a surface concentric with the axis of said.gear,said lever having agportion forming atapered recess with-saidsec-0nd member, aballin said recess and a second lever carriedby saidfirstlever forn'e leasing said ball from wedgingposition.

4:. In a lens surfacingmachme, the combinatlon ofarotatablymounted-tool;a lens guiding frame having a pair of-a'pertures'adapted to form bearings and-l0cated"re- 'spectively aboveand below saidt0ol,-a two part bracket'having onepart provided with i a pivot pin,means whereby' said part may be ad usted to raise and lower said p votpin to engageone or theother of said aper-- tures, means for rigidlysecuring 1 said frame to said-pivotpin, means forpivotallysupportingsaid bracket to "swing ;ina plane at-right angles to the "axisof said tool and means for: holding said bracket immovable. 5. In a lenssurfacing 1nach1ne,--the-'come.

binaticn of a surfacing member; a lens holding member,--a frameformovlng one .of said members relative to the 5 other,-- said framehaving a pair of bearingsockets whose axes lie respectively above andbelow "said surfacing memberand extend at right angles to the axisthereof, a supportingadevice for said frame having-a member carrying-:21post adapted. to fit said socketsanduneans whereby said.- .last imember'mayx-be adjust ed I to -cause: it to engage eitheratheaoneror the otherof saidisockets istdesired;

6. In a lens surfacing. machineythe rombination of a rotatably mountedsurfacing tool, a lenscarrying member, a framefor moving said lenscarrying member across the-face of said tOOl,-S@l(l frame having apairof fixed'bearing socketswhose axes he respectively above and belowthe face of said tate upon a vertical axis, a lens guiding ,65 a lensagainst said tool andhaving -apair of frame having means for resilientlypressing horizontal bearing sockets located respectively above and Ibelow' the plane of said tool,-a bracket having apost adapted to engagein either ofsaid socketsya baseghaving a verticalbeari'nggpost, a secondbracket pivoted-onsaid bearlng post and having an adjustable connectionwithsaid first bracket to permit thelatter'being raised and lowered andinserted in theone'zor the other of said sockets, a set screw forclamping together said base and said second bracket when the frame is tobe swung about said first post and a set screw for clamping to-,

gether said frame and said first post when the frame is to be swungabout said basepost.

8. In a lenssurfac ng'machlne, the combinatlon of a rotatably mountedsurfacing ,lap, ;a lens Guiding frame; a supporting ,de

vice for sai frame pivotally mounted on an fl-XlSPflIillflBl with theaxis of said lap, said frame havin g twoi fixed sockets locatedrespectively above andbelow said lap and said -device comprising arelatively adjustable-partada pted-to be shifted to pivotally engage inone or the other of said sockets.

In testlmony whereof I affix my signa ture.

CHAUNGE'Y'W. How-I N1).

